Positioning cables in underground communication conduits which extend for several thousand feet has long been a problem. Such is particularly true when it is desired to position an additional cable or cables into a conduit that already has a cable in it. That cable, particularly because of its plastic jacket, provides a great deal of friction to the new cable as it is attempted to be inserted into the conduit. As a result, the new or the existing cable may be easily damaged due to that friction. Such is particularly true when the cable in the conduit is ungulating which causes the cable being introduced to take a sinuous, fraction-laden path.
One solution to this problem is to position one or more high density polypropylene tubes, often known as innerducts, in the conduit to divide it into a number of compartments into which a cable can be inserted. The purpose of these innerducts is to assure that one cable does not rub against another cable while being inserted into, or while coexisting in, a conduit. However, it is not easy to insert a cable into these innerducts because of the friction afforded by the cable jacket against the walls of the innerduct. Moreover, the innerducts are provided at the installation site on a reel, and because they have reel memory when positioned in a conduit, it is even more difficult to install a cable in these innerducts as they spiral through a conduit. Also, because they spiral through a conduit, most often several of these rigid innerducts must be installed during the initial installation of the conduit even though they may not be needed for several years, if at all. Thus, the user must prepay for the innerducts and their installation which could be wasted money.
An extremely successful solution to this problem is a fabric innerduct sold under the trademark MAXCELL® by the TVC Communications Division of WESCO Distribution, Inc. and shown in U.S. Pat. No. 6,262,371 which is incorporated by reference for whatever details may be necessary to understand the present invention. This innerduct is first positioned in a conduit and divides the conduit into longitudinally extending compartments. When a cable is positioned in one of the compartments, a pull tape or rope that is in another compartment is utilized to pull a second cable into that compartment. Because there is fabric between the cables, the friction is not on the cable jacket but on the fabric which makes installation easier.
However, a problem can exist when using these innerducts in small diameter conduits which extend long distances. In these small conduits, the fabric innerduct takes up much of the space in the conduit and the tape or rope may tend in lock up in the innerduct thereby impeding the ability to pull in a cable.
As a result, the need exists to eliminate the need for any form of innerduct in a conduit.